welding swing arm
- Thread starter 808blaster
- Start date
look at the state of they welds too holy S#it!! You wonder why this has failed. Back to drawing board my friend 
look at the state of they welds too holy S#it!! You wonder why this has failed. Back to drawing board my friend
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Had the same problem myself
This is the result of twisting stresses on the beam length of the swingarm.
Very common on hard ridden Blasters due to uneven loads on each wheel or beam of the swingarm.
I haven't seen it result in a sudden or catastrophic failure, anyone?
I welded my crack up, it didn't seem like chrome-moly (the frame is) and took weld well.
You can put a thin plate over it. I'd recommend tacks rather than a continuous weld on the plate.
After all the rhetoric, I might need nomex shorts for my next comments.
The stock arm is the lightest design I have seen, which is what you want in suspension parts, right?
Less unsprung weight is better, as long as you have the strength. The stock arm does well.
The whole point of "engineering" is "just enough" strength and no catastrophes. Stock does this.
My son has a 4" aftermarket swingarm that failed. No big deal, we spotted the cracks on the cross tube.
So what does he run now? A modified stock arm... Hey, hey, HEY! Stop throwing that stuff at me!!!
Seriously, as AWK08 says, it is pretty hard to weld sheetmetal and expect strength.
All the bending moment occurs between the two opposing forces.
The wheels and carrier is forced up and the shock mount forces down on the arm.
Anything between these points better be hellish strong, especially if you are adding leverage.
The strongest metal on these arms is the 1/4" carrier mount at the end of the swingarm;
Not only is that 1/4" plate strong, it is mild steel and easy to weld to, especially over the 4" length.
So I tried it on my KTM 250 powered Blaster.
This was a 2" extension. Welding the heavy steel to heavy steel is not hard for a good welder and can be trusted. It is very open for inspection and the weld is in the least stressed plane.
Egad that's an ugly looking weld! We welded it in short stitches to avoid bending.
Later ones we did a continual weld over a couple tacks that looks a lot better.
The horizontal plate is to get rid of any side to side bending. A tube could have been used too.
Does it work?
This was done back in 2012 and still holding together on my KTM powered monster.
I am mainly a trail rider, but I wheelie over logs and rocks and I have enough power to wheelie at any speed and not loose rpm on any hill. So far no cracks or fatigue.
My son and I have 4 or 5 Blasters on the go around here. He of course wanted more, so he made up a 3" extension and with its success made a 4" extension. Picture that inserted plate above being square. It is still running with no problems.
All the things that Awk08 and Ken and others have said against modified swingarms are true. Poor design and poor welds (embarrassed to show mine, not a work of art) will result in broken parts and possible serious injury. I am agreeing with them. Just showing what is possible with a little thought.
Steve
Smallest displacement, guess who is quickest...
This is the result of twisting stresses on the beam length of the swingarm.
Very common on hard ridden Blasters due to uneven loads on each wheel or beam of the swingarm.
I haven't seen it result in a sudden or catastrophic failure, anyone?
I welded my crack up, it didn't seem like chrome-moly (the frame is) and took weld well.
You can put a thin plate over it. I'd recommend tacks rather than a continuous weld on the plate.
After all the rhetoric, I might need nomex shorts for my next comments.
The stock arm is the lightest design I have seen, which is what you want in suspension parts, right?
Less unsprung weight is better, as long as you have the strength. The stock arm does well.
The whole point of "engineering" is "just enough" strength and no catastrophes. Stock does this.
My son has a 4" aftermarket swingarm that failed. No big deal, we spotted the cracks on the cross tube.
So what does he run now? A modified stock arm... Hey, hey, HEY! Stop throwing that stuff at me!!!
Seriously, as AWK08 says, it is pretty hard to weld sheetmetal and expect strength.
All the bending moment occurs between the two opposing forces.
The wheels and carrier is forced up and the shock mount forces down on the arm.
Anything between these points better be hellish strong, especially if you are adding leverage.
The strongest metal on these arms is the 1/4" carrier mount at the end of the swingarm;
Not only is that 1/4" plate strong, it is mild steel and easy to weld to, especially over the 4" length.
So I tried it on my KTM 250 powered Blaster.
This was a 2" extension. Welding the heavy steel to heavy steel is not hard for a good welder and can be trusted. It is very open for inspection and the weld is in the least stressed plane.
Egad that's an ugly looking weld! We welded it in short stitches to avoid bending.
Later ones we did a continual weld over a couple tacks that looks a lot better.
The horizontal plate is to get rid of any side to side bending. A tube could have been used too.
Does it work?
This was done back in 2012 and still holding together on my KTM powered monster.
I am mainly a trail rider, but I wheelie over logs and rocks and I have enough power to wheelie at any speed and not loose rpm on any hill. So far no cracks or fatigue.
My son and I have 4 or 5 Blasters on the go around here. He of course wanted more, so he made up a 3" extension and with its success made a 4" extension. Picture that inserted plate above being square. It is still running with no problems.
All the things that Awk08 and Ken and others have said against modified swingarms are true. Poor design and poor welds (embarrassed to show mine, not a work of art) will result in broken parts and possible serious injury. I am agreeing with them. Just showing what is possible with a little thought.
Steve
Smallest displacement, guess who is quickest...
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So lets get this straight. You come on here asking if this swingarm can be extended by welding. You get an honest answer. You don't like the answer and then proceed to tell us how you are confident in your welding skills. Then complain people are stepping over you and jumping down your throat. Then you start bashing a broken repaired factory swingarm. But we are so childish. Get a pack of clues before you start believing in your welding skills. If you are such a damn good welder than why fix stock thin junk?? Are you only a welder and not a fabricator? Nothing worse than someone coming in here asking questions then contradicting everything respectable members post and start saying they are treating you unfairly. No, you are acting like a know it all and master welder and wont take good, honest advise on the situation. Hell you posted a pic of a stainless tig weld not a steel mig weld... Anyone who thinks about extending a stock cracked swingarm is clueless, I don't care how good you think you are at welding. Are you related to yb200? He tried that endeavor once. Hell while you are at it mine as well extend the a-arms to. But why stop there mine as well extend the axle. You welding skills are so top notch I have faith in you. Just post pics please. What next you are going to start complaining that I was to harsh on you. Sometimes you need to put it in perspective for the other know it all to understand. Comes out asking a question but already has their mind made up on what they are going to do. Why ask a question then. Just do it and have your gf,mom,dad etc send us a copy of the obituary so we can post it in the next stock swingarm thread. If you want to knock the broken picks welding than you can obviously see the one best posted is top notch quality. That thing will never break,lol . Worst looking extended swingarm posted on this forum. Sorry best but its true. So with all this said your next post better have this swingarm repaired, extended, welded and a video would be nice. Then if you dare send it this way and we will put "40 tons of fun" on it yb style!! knowmsayinn
AS you said it best... Back to the drawing board my friend. Should be more like back to the grade school class chalk board for the ones who can't comprehend basic knowledge.
I'd like to know where you experienced this ?
I went back thru your 19 posts and don't see anything except in this thread with you not accepting my views that extended stock swingarms are junk and a big liability
Here's a mig shot Being a mechanical engineer I know my materials was just arguing my point as we all do you guys are specialists in this field so yeah maybe I was wrong I still believe I could do one but what the heck it was just to keep me busy. Don't want you guys taking the wrong impression of me it got a bit heated...
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Absolutely true, no matter how good the weld, rusty sheet metal isn't a good place to start.
These 'motherhood issue' posts have a way of getting overly passionate, then personal, then getting personally offensive (often thinly veiled as humour), then getting overly defensive.
Yeah, I've got so little aesthetic ability I gotta get a note from a lady to buy tinted paint!
Seriously, I am truly about function over form. Michelangelo, I ain't.
Git'er done! And I don't have time for polishing.
In my jobs dealing with crews of tradesmen and SAR Techs I am used to the polarization, exaggeration and chest puffing that comes with guys that work hard and hold strong opinions. Disagreement does not minimize your value. It does build diversity and alternate approaches. So YB my a$$, or yell at me or call me a fool. You are not going to intimidate me into validating your narrow viewpoint. That belongs over in the Mid-east where they are so good at it.
My obituary has not happened in the past 55 years, and in 4 years my cracked repaired and extended swingarm has not broken, and neither have either of my son's even longer arms. I have no fear that you will be proven right on at least one of those predictions. I do plan to die, just not in the next few decades...
So, what am I doing here?
I want to learn.
So why do I post subjects that flow against the crowd?
Why don't I post picts of wonderful polished exhausts and massive jig built swingarms?
That has been done. Why follow the lemmings? Do they really know where they are going?
Or can we learn something going off in another direction?
Scientific method.
Ask a Question
Do Background Research
Construct a Hypothesis
Test Your Hypothesis by Doing an Experiment
Analyze Your Data and Draw a Conclusion
Communicate Your Results
You guys are the peer review group. As well as much of the background research. Glad to have you.
So ask yourself, what new thing have you added to the body of knowledge here?
Steve, from the frozen North
These 'motherhood issue' posts have a way of getting overly passionate, then personal, then getting personally offensive (often thinly veiled as humour), then getting overly defensive.
Yeah, I've got so little aesthetic ability I gotta get a note from a lady to buy tinted paint!
Seriously, I am truly about function over form. Michelangelo, I ain't.
Git'er done! And I don't have time for polishing.
In my jobs dealing with crews of tradesmen and SAR Techs I am used to the polarization, exaggeration and chest puffing that comes with guys that work hard and hold strong opinions. Disagreement does not minimize your value. It does build diversity and alternate approaches. So YB my a$$, or yell at me or call me a fool. You are not going to intimidate me into validating your narrow viewpoint. That belongs over in the Mid-east where they are so good at it.
My obituary has not happened in the past 55 years, and in 4 years my cracked repaired and extended swingarm has not broken, and neither have either of my son's even longer arms. I have no fear that you will be proven right on at least one of those predictions. I do plan to die, just not in the next few decades...
So, what am I doing here?
I want to learn.
So why do I post subjects that flow against the crowd?
Why don't I post picts of wonderful polished exhausts and massive jig built swingarms?
That has been done. Why follow the lemmings? Do they really know where they are going?
Or can we learn something going off in another direction?
Scientific method.
Ask a Question
Do Background Research
Construct a Hypothesis
Test Your Hypothesis by Doing an Experiment
Analyze Your Data and Draw a Conclusion
Communicate Your Results
You guys are the peer review group. As well as much of the background research. Glad to have you.
So ask yourself, what new thing have you added to the body of knowledge here?
Steve, from the frozen North
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/\ you said it yourself
I look at this differently, as I've broken every make of swingarm made, except the Lonestar roundhouse which I just aquired and have yet to run....I mean break
I'd rather air on the side of caution than promote something I wouldn't trust myself, especially a part as vital as a swingarm, and see it break on some youngster and they get hurt or even killed.
thats why we've collectively, yet unofficially, prohibited the fabrication and sale of hacked together stock swingarms on here, after the one I linked to above broke under a 95 pound kid, the old YB200 swingers breaking, and the one on my spare black bike which is cracked in numerous places.
I've seen more broken ones than ones that held together, but IMO.....even one is too many.
do we really know the intended use for fabricating suggestions of vital suspension components ?
not everyone rides the same...riding up river beds and skipping a few logs is a far cry from 30' jumps on an mx track, who's riding these things where for us to suggest them ?
I like this, let me try it.........
Scientific method.
Ask a Question - can a stamped sheet metal swinger be extended ?
Do Background Research - hmmm, some guys on BF do it
Construct a Hypothesis - I can weld this to that and it'll be strong
Test Your Hypothesis by Doing an Experiment - slid 1-1/2" x 3/4" mild steel tubing inside from end to end and welded it up, making stitch welds to not overheat the surrounding metal, extended 2" in the middle.
Analyze Your Data and Draw a Conclusion - junk cracked within a few rides, too much leverage for original steel
Communicate Your Results - I must ride like a maniac, but maybe others do too, let me not promote this on BF
that is all, carry on
btw....who knows why flourescent orange shows up in pics and vids like it is in steve's pics above ? not the first time I've seen that.
I look at this differently, as I've broken every make of swingarm made, except the Lonestar roundhouse which I just aquired and have yet to run....I mean break
I'd rather air on the side of caution than promote something I wouldn't trust myself, especially a part as vital as a swingarm, and see it break on some youngster and they get hurt or even killed.
thats why we've collectively, yet unofficially, prohibited the fabrication and sale of hacked together stock swingarms on here, after the one I linked to above broke under a 95 pound kid, the old YB200 swingers breaking, and the one on my spare black bike which is cracked in numerous places.
I've seen more broken ones than ones that held together, but IMO.....even one is too many.
do we really know the intended use for fabricating suggestions of vital suspension components ?
not everyone rides the same...riding up river beds and skipping a few logs is a far cry from 30' jumps on an mx track, who's riding these things where for us to suggest them ?
I like this, let me try it.........
Scientific method.
Ask a Question - can a stamped sheet metal swinger be extended ?
Do Background Research - hmmm, some guys on BF do it
Construct a Hypothesis - I can weld this to that and it'll be strong
Test Your Hypothesis by Doing an Experiment - slid 1-1/2" x 3/4" mild steel tubing inside from end to end and welded it up, making stitch welds to not overheat the surrounding metal, extended 2" in the middle.
Analyze Your Data and Draw a Conclusion - junk cracked within a few rides, too much leverage for original steel
Communicate Your Results - I must ride like a maniac, but maybe others do too, let me not promote this on BF
that is all, carry on
btw....who knows why flourescent orange shows up in pics and vids like it is in steve's pics above ? not the first time I've seen that.
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Good points made AWK, but following that line of thought, should we recommend power adding mods?
We don't know who is doubling the hp of Blasters? Couldn't some kid get hurt with that?
Imposed social responsibility is looking after the other guy cuz we want to, regardless of their desires.
"back to the grade school class chalk board for the ones who can't comprehend basic knowledge"
The irony is not lost on me, for sure. Somewhat like my "defensive" comment?
My favourite colour! It kinda jumps at ya, doesn't it?
Since giving up Army green, day-glow orange has been my new favourite thing.
Used to "Search and Destroy", just have to soften the plan a bit now when I find them!
Steve
We don't know who is doubling the hp of Blasters? Couldn't some kid get hurt with that?
Imposed social responsibility is looking after the other guy cuz we want to, regardless of their desires.
"back to the grade school class chalk board for the ones who can't comprehend basic knowledge"
The irony is not lost on me, for sure. Somewhat like my "defensive" comment?
My favourite colour! It kinda jumps at ya, doesn't it?
Since giving up Army green, day-glow orange has been my new favourite thing.
Used to "Search and Destroy", just have to soften the plan a bit now when I find them!
Steve
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